The Arizona gunman who shot former US Representative Gabrielle Giffords has pleaded guilty to killing six others and wounding 13 people.

Jared Loughner will remain in prison with no possibility of appeal for his crimes last year in Tucson - but will not face the death penalty.

The New York Times reported that Loughner's psychologist Dr Christina Pietz had told the court Loughner had some measure of regret for his actions, telling her "I especially cried for the child” referring to 9-year-old Christina Taylor Green, whom he shot dead.

Former Congresswoman Gabrielle Giffords, who is recovering from the shooting

Loughner fired 31 shots into the crowd meeting Republican Giffords, who was his intended target, until he was subdued by passers-by.

Doctors had to perform emergency surgery to extract skull fragments from Giffords' brain and she was placed in an induced coma.

The former congresswoman, who had to resign her position, has had to relearn to walk and speak but is reportedly recovering well.

The outcome was welcomed by some victims, including Giffords, as a way to avoid a trial and wrangling over a death sentence.

She said in a statement: "The pain and loss caused by the events of 8 January 2011, are incalculable.

"Avoiding a trial will allow us - and we hope the whole Southern Arizona community - to continue with our recovery."

Attorney Judy Clark and Jared Loughner sit before the judge in federal court in Tucson, Ariz. as shown in this artists' rendering

Others killed included Gabe Zimmerman, Giffords' community outreach director and Judge John Roll, chief judge of the US District Court for Arizona.

In May, he was judged incompetent to stand trial after delivering an incomprehensible rant in court

Ms Giffords did not attend the hearing, but husband, Mark Kelly, said they had been kept informed of the outcome.